Leave the duration alone. You'll go backwards!
NYTSKY made 550 on the same turbo with 256 and 264 on 25 psi ( IIRC )
Turn it up! No point having such a monster turbo and running it on fairy boost.
^^ seems to be a hell of a lot of work and a potential nightmare. How much power are you after? The small housings have been proven to do over by a few people to do 500 wkw.
Mine weighed in at 1580 kg. Only weight oust of it was wheel, jack and boot interior. Where is the extra weight coming from? 80 odd Kgs doesn't exactly hide under a seat.
Must be that fuel pump, Mick .